Thing is, he may not need many sessions at all to give him some things to start managing his life and make things easier. I got shown the brushing protocol and given my brush in the second session, and it's been one of the most useful things for me. I think I've had 4 sessions over this year. That's it. My OT is also happy for me to email to ask quick questions.

To give you some more ammunition:
Why OT is helpful:
- When I'm heading to overload/meltdown, I now can mostly tell that I'm heading in that direction and use mitigation techniques to stop it.
- When I'm going to be doing something that I know is going to be sensory stressful, I can work to calm my body before and then throughout
- Understanding the different aspects of how SPD affects things, things that I hadn't realised before.
- Figuring out what is calming - for me classical music, yoga, running my hands through marbles/smooth rocks, weighted blankets (wonderful!), firm hugs, brushing protocol, getting back to nature (out somewhere on a walk with nothing but nature sounds), exercise. When driving on long trips I now put three wheat heat packs that are designed for draping around your neck/shoulders across my upper legs. The weight helps keep my body calmer.
- Understanding limits - that when you put multiple things together that are stressful over a period of time you're more likely to end up with a bad outcome and need to do more mitigation
- Rearranging when I shop so that I don't get triggered by the shopping centre (now mostly first thing on Saturday morning, so much quieter then!)

For us, there can also be a fear - who am I without this? If I get it 'dealt' with, who am I? Thing is, it's always going to be there, but I can manage my life a lot more easily now.

Unfortunately it sounds like you might have to be the one to learn about it at the moment, but it's great that you're willing to. I've had varying reactions from telling people in my life about SPD, but mostly supportive, and that's a huge help.